From 849369d6c66d3054688672f97d31fceb8e8230fb Mon Sep 17 00:00:00 2001 From: root Date: Fri, 25 Dec 2015 04:40:36 +0000 Subject: initial_commit --- Documentation/DocBook/v4l/vidioc-encoder-cmd.xml | 204 +++++++++++++++++++++++ 1 file changed, 204 insertions(+) create mode 100644 Documentation/DocBook/v4l/vidioc-encoder-cmd.xml (limited to 'Documentation/DocBook/v4l/vidioc-encoder-cmd.xml') diff --git a/Documentation/DocBook/v4l/vidioc-encoder-cmd.xml b/Documentation/DocBook/v4l/vidioc-encoder-cmd.xml new file mode 100644 index 00000000..b0dde943 --- /dev/null +++ b/Documentation/DocBook/v4l/vidioc-encoder-cmd.xml @@ -0,0 +1,204 @@ + + + ioctl VIDIOC_ENCODER_CMD, VIDIOC_TRY_ENCODER_CMD + &manvol; + + + + VIDIOC_ENCODER_CMD + VIDIOC_TRY_ENCODER_CMD + Execute an encoder command + + + + + + int ioctl + int fd + int request + struct v4l2_encoder_cmd *argp + + + + + + Arguments + + + + fd + + &fd; + + + + request + + VIDIOC_ENCODER_CMD, VIDIOC_TRY_ENCODER_CMD + + + + argp + + + + + + + + + Description + + + Experimental + + This is an experimental +interface and may change in the future. + + + These ioctls control an audio/video (usually MPEG-) encoder. +VIDIOC_ENCODER_CMD sends a command to the +encoder, VIDIOC_TRY_ENCODER_CMD can be used to +try a command without actually executing it. + + To send a command applications must initialize all fields of a + &v4l2-encoder-cmd; and call + VIDIOC_ENCODER_CMD or + VIDIOC_TRY_ENCODER_CMD with a pointer to this + structure. + + The cmd field must contain the +command code. The flags field is currently +only used by the STOP command and contains one bit: If the +V4L2_ENC_CMD_STOP_AT_GOP_END flag is set, +encoding will continue until the end of the current Group +Of Pictures, otherwise it will stop immediately. + + A read() call sends a START command to +the encoder if it has not been started yet. After a STOP command, +read() calls will read the remaining data +buffered by the driver. When the buffer is empty, +read() will return zero and the next +read() call will restart the encoder. + + A close() call sends an immediate STOP +to the encoder, and all buffered data is discarded. + + These ioctls are optional, not all drivers may support +them. They were introduced in Linux 2.6.21. + + + struct <structname>v4l2_encoder_cmd</structname> + + &cs-str; + + + __u32 + cmd + The encoder command, see . + + + __u32 + flags + Flags to go with the command, see . If no flags are defined for +this command, drivers and applications must set this field to +zero. + + + __u32 + data[8] + Reserved for future extensions. Drivers and +applications must set the array to zero. + + + +
+ + + Encoder Commands + + &cs-def; + + + V4L2_ENC_CMD_START + 0 + Start the encoder. When the encoder is already +running or paused, this command does nothing. No flags are defined for +this command. + + + V4L2_ENC_CMD_STOP + 1 + Stop the encoder. When the +V4L2_ENC_CMD_STOP_AT_GOP_END flag is set, +encoding will continue until the end of the current Group +Of Pictures, otherwise encoding will stop immediately. +When the encoder is already stopped, this command does +nothing. + + + V4L2_ENC_CMD_PAUSE + 2 + Pause the encoder. When the encoder has not been +started yet, the driver will return an &EPERM;. When the encoder is +already paused, this command does nothing. No flags are defined for +this command. + + + V4L2_ENC_CMD_RESUME + 3 + Resume encoding after a PAUSE command. When the +encoder has not been started yet, the driver will return an &EPERM;. +When the encoder is already running, this command does nothing. No +flags are defined for this command. + + + +
+ + + Encoder Command Flags + + &cs-def; + + + V4L2_ENC_CMD_STOP_AT_GOP_END + 0x0001 + Stop encoding at the end of the current Group Of +Pictures, rather than immediately. + + + +
+ + + + &return-value; + + + + EINVAL + + The driver does not support this ioctl, or the +cmd field is invalid. + + + + EPERM + + The application sent a PAUSE or RESUME command when +the encoder was not running. + + + + + + + -- cgit v1.2.3